1. Field of the Invention
This invention relates generally to flow control valves. It relates especially to a valve for controlling the flushing of urinals or toilets, although the invention also has application to other types of valves.
2. Background Information
A typical flush control valve includes a housing with an inlet, an outlet and a valve seat located in the flow path between the inlet and outlet. A valve member in the housing is movable toward and away from the valve seat to control the flow of water from the inlet to the outlet. The valve member is moved between these two positions by an actuator of some kind. The actuator may be a lever arm or button which is linked to the valve member mechanically and/or hydraulically. Alternatively, the actuator may be an electromechanical device such as a solenoid controlled by a proximity sensor which senses the presence of someone positioned close to the valve. In any event, the typical flush control valve is designed so that once the valve member is unseated by the actuator, the valve remains open for a selected period of time before shutting off. That valve-open time may be controlled hydraulically in the case of a manually actuated valve or electronically in the case of a solenoid actuated valve.
During the operating life of flow control valves of this general type it becomes necessary to clean, repair or replace various valve parts such as seals, gaskets, filters and the like. In the case of the valves whose on-time is controlled hydraulically by water flow through small orifices or passages in the valves, dirt and minerals can accumulate those passages, thereby altering the on time of the valve and necessitating a cleaning of those passages. When such maintenance or repair is required, it is necessary to stop the flow of water upstream from the valve seat. For this reason, a manual shut off valve is invariably installed in the water line feeding the flow control valve.
In some cases, that manual shut off valve may be difficult to turn because it has not been used for a long period of time. In other instances, the shut off valve is located in a hard-to-reach place behind a fixture or even inside a partition. In a worst case scenario, there may be no such valve requiring the water mains to be turned off. Resultantly, a simple repair of a flow control valve may take an excessive amount of time and effort because of the necessity to turn off the water flow to the valve.